title: A defective ABC transporter of the MRP family, responsible for the bean lpa1 mutation, affects the regulation of the phytic acid pathway, reduces seed myo-inositol and alters ABA sensitivity.
abstract: • We previously identified the lpa1 (low phytic acid) 280-10 line that carries a mutation conferring a 90% reduction in phytic acid (InsP(6) ) content. In contrast to other lpa mutants, lpa1(280-10) does not display negative pleiotropic effects. In the present paper, we have identified the mutated gene and analysed its impact on the phytic acid pathway. • Here, we mapped the lpa1(280-10) mutation by bulk analysis on a segregating F(2) population, an then, by comparison with the soybean genome, we identified and sequenced a candidate gene. The InsP(6) pathway was analysed by gene expression and quantification of metabolites. • The mutated Pvmrp1(280-10) cosegregates with the lpa1(280-10) mutation, and the expression level of several genes of the InsP(6) pathway are reduced in the lpa1(280-10) mutant as well as the inositol and raffinosaccharide content. PvMrp2, a very similar paralogue of PvMrp1 was also mapped and sequenced. • The lpa1 mutation in beans is likely the result of a defective Mrp1 gene (orthologous to the lpa genes AtMRP5 and ZmMRP4), while its Mrp2 paralog is not able to complement the mutant phenotype in the seed. This mutation appears to down-regulate the InsP(6) pathway at the transcriptional level, as well as altering inositol-related metabolism and affecting ABA sensitivity.
authors.affiliation: Istituto di Biologia e Biotecnologia Agraria, CNR, Milano, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Panzeri
authors.affiliation: Dipartimento di Produzione Vegetale, Università degli Studi di Milano, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Cassani
authors.affiliation: Dipartimento di Genetica e Microbiologia, Università di Pavia, Pavia, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Doria
authors.affiliation: Istituto di Biologia e Biotecnologia Agraria, CNR, Milano, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Tagliabue
authors.affiliation: Dipartimento di Chimica, Università di Modena, Modena, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Forti
authors.affiliation: Unità di ricerca per l'Orticoltura CRA, Montanaso Lombardo, Lodi, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Campion
authors.affiliation: Istituto di Biologia e Biotecnologia Agraria, CNR, Milano, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Bollini
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Brearley
authors.affiliation: Dipartimento di Produzione Vegetale, Università degli Studi di Milano, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Pilu
authors.affiliation: Dipartimento di Genetica e Microbiologia, Università di Pavia, Pavia, Italy.
authors.forename: Erik
authors.initials: E
authors.lastname: Nielsen
authors.affiliation: Istituto di Biologia e Biotecnologia Agraria, CNR, Milano, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Sparvoli
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D000040:Abscisic Acid / Q000494:pharmacology*; D000595:Amino Acid Sequence; D002874:Chromosome Mapping; D018525:Germination / Q000187:drug effects / Q000235:genetics; D007294:Inositol / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D027805:Phaseolus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D010833:Phytic Acid / Q000096:biosynthesis; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D012639:Seeds / Q000187:drug effects / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction
chemical_list: D018528:ATP-Binding Cassette Transporters; D010940:Plant Proteins; D007294:Inositol; D000040:Abscisic Acid; D010833:Phytic Acid